The gel mix naturally makes the water denser than it normally would be. So what are you forgetting about? If you said the filter and the circulation pump then you thought right. Whether the filter is a paper cartridge or a sand filter, you're going to ruin either one. as for the pump, it's designed to move straight water. Make it denser and the pump may fry trying to move the gel.
And how do you intend to clean out the pool if the pump can't be used?
Hate to rain on your parade but the sand filter and pumps are not cheap to replace. I'm managed enough hotel properties to have some experience in having to purchase new ones.